Rabbits, deer, kangaroos and domestic stock are all browsers of young trees and grasshoppers or other defoliating insects can also damage young seedlings. Options for seedling protection might include shooting and poisoning (where acceptable), repellents, tree guards, fencing or deterrents and will depend of the area, period of risk and landowners resources.
Deterrants
Where native animals are damaging seedlings, one form of deterrent, for small areas, can be to place old tyres or branches, especially of prickly species, over the re-vegetation area.
Fencing
Exclusion fencing is the most cost-effective way of protecting plantsfrom livestock and from native animals such as
kangaroos. Designs vary from prefabricated wire fencing, electric fencing and traditional post and wire
fencing and will range in cost per hectare. Blocking any gaps beneath the bottom wires may be needed to prevent digging under the fencelines.
Tree Guards
Tree Guards protect plants from grazing animals and provide a beneficial microenvironment for the plant's early establishment by protecting from drying winds and extreme temperatures protecting from frost and heat. The visual impact of tree guards can also raise awareness of the revegetation activity. For large scale projects - guarding is not usually a practical option, and it is important to consider:
A wide range of guards are available including:
milk cartons
pros - cost effective, biodegradeable, don't cook seedling
cons - small, can look messy
plastic corflute
pros - durable, reusable, don't need restaking
cons - expensive,
plastic sleeves
pros - cost effective
cons - not biodegradeable, need restaking, collapse in wind, need to be removed
Pest Control
Landowners should be aware of the risks of insect damage and watch for signs of excessive defoliation. Although most species can tolerate quite high levels of defoliation if trees are repeatedly attacked pesticide treatment may also be warranted.
Controlling insect pests is not always easy or practical but often controls need to be applied to lessen the impact of the insects on tree growth and survival. The methods of dealing with insect pest problems will depend on the particular insect involved, the size of the trees and the extent of the problem. It is very important to detect insect pests early, before major damage has occurred.
If broadleaf weeds like capeweed are present Red Legged Earth Mite could be a problem and areas of couch grass and kikuyu mean that black beetle and grasshoppers could be an issue in the establishment phase.
Natural control mechanisms can be sufficient to prevent the pest insect from increasing in numbers to such an extent that damage reaches an unacceptable level. These mechanisms involve
Physical/mechanical Control
These methods of control are often not considered as they may not be practical on a large scale, they are very effective and environmentally safe. Such methods include removal and destruction of infested material and the use of mechanical barriers. For example, sticky bands can be placed around scale infested tree trunks to prevent ants
attending the scale.
Chemical Control can achieve rapid control of an insect that is causing damage. The decision to spray should not be taken lightly. At present there is little or no information available on damage levels or economic thresholds for insect pests on eucalypts. Some points to consider in making the decision to spray:
A major problem in using chemicals to control insect pests in plantations is that few are registered for use in forestry situations. All Australian States and Territories have different control-of-use laws which govern how registered products can be used.
Deterrants
Where native animals are damaging seedlings, one form of deterrent, for small areas, can be to place old tyres or branches, especially of prickly species, over the re-vegetation area.
Fencing
Exclusion fencing is the most cost-effective way of protecting plantsfrom livestock and from native animals such as
kangaroos. Designs vary from prefabricated wire fencing, electric fencing and traditional post and wire
fencing and will range in cost per hectare. Blocking any gaps beneath the bottom wires may be needed to prevent digging under the fencelines.
Tree Guards
Tree Guards protect plants from grazing animals and provide a beneficial microenvironment for the plant's early establishment by protecting from drying winds and extreme temperatures protecting from frost and heat. The visual impact of tree guards can also raise awareness of the revegetation activity. For large scale projects - guarding is not usually a practical option, and it is important to consider:
- the cost associated with purchasing guards and stakes;
- the time and labour involved and transport of materials to the site;
- not all guards are biodegradable and will require follow up removal;
A wide range of guards are available including:
- cardboard drink/milk cartons with slits cut in two opposite corners for either bamboo or
- rigid plastic guards
- plastic sleeves;
- mesh guards, either plastic or galvanised netting wire.
milk cartons
pros - cost effective, biodegradeable, don't cook seedling
cons - small, can look messy
plastic corflute
pros - durable, reusable, don't need restaking
cons - expensive,
plastic sleeves
pros - cost effective
cons - not biodegradeable, need restaking, collapse in wind, need to be removed
Pest Control
Landowners should be aware of the risks of insect damage and watch for signs of excessive defoliation. Although most species can tolerate quite high levels of defoliation if trees are repeatedly attacked pesticide treatment may also be warranted.
Controlling insect pests is not always easy or practical but often controls need to be applied to lessen the impact of the insects on tree growth and survival. The methods of dealing with insect pest problems will depend on the particular insect involved, the size of the trees and the extent of the problem. It is very important to detect insect pests early, before major damage has occurred.
If broadleaf weeds like capeweed are present Red Legged Earth Mite could be a problem and areas of couch grass and kikuyu mean that black beetle and grasshoppers could be an issue in the establishment phase.
Natural control mechanisms can be sufficient to prevent the pest insect from increasing in numbers to such an extent that damage reaches an unacceptable level. These mechanisms involve
- parasitoids - other insects such as flies and wasps.
- predators include birds, spiders and insects such as shield bugs, robberflies, lacewings, hoverflies, ladybirds, predatory beetles, dragonflies and praying mantids.
- diseases may be bacteria, viruses or fungi.
Physical/mechanical Control
These methods of control are often not considered as they may not be practical on a large scale, they are very effective and environmentally safe. Such methods include removal and destruction of infested material and the use of mechanical barriers. For example, sticky bands can be placed around scale infested tree trunks to prevent ants
attending the scale.
Chemical Control can achieve rapid control of an insect that is causing damage. The decision to spray should not be taken lightly. At present there is little or no information available on damage levels or economic thresholds for insect pests on eucalypts. Some points to consider in making the decision to spray:
- Smaller trees can tolerate less damage that larger ones
- Damage in spring or early summer will cause little loss of growth as the trees quickly put on new foliage.
- Damage in autumn will only cause a reduction in growth if there is approximately 30-50% or more defoliation.
- Defoliation of the lower part of the tree has little effect on growth.
A major problem in using chemicals to control insect pests in plantations is that few are registered for use in forestry situations. All Australian States and Territories have different control-of-use laws which govern how registered products can be used.